Raspberry Pi is a low-cost computer. It costs only 2950/- Rs. This low-cost computer can be used by students, at home, in schools and coaching institutes. It also comes with GPIO and can be used to connect various sensors. This means it can be used to make various IoT projects.
It is a computer, this means you can install an operating system in it with various development tools. This means you do not burn the program in it like other development boards (Arduino).
There are many operating systems that can be installed in RaspberryPi but there is an operating system developed specially for Raspberry Pi, named RESPBIAN.
The video shows you steps by steps procedure to install RESPBIAN in RaspberryPi. Follow the steps and let me know in the comments below if you face any problem.